To reimburse the FDA/CDER for services provided to support NIH/NIDA's drug discovery programs for medications of potential use against addiction to controlled substances or tobacco. FDA/CDER will: a) support the development, validation, and application of computational toxicology software of mutual benefit to the FDA/CDER and NIH/NIDA b) Estimate the toxicological profile of potential therapeutic compounds under evaluation by the NIH/NIDA Drug Discovery Programs, employing computational toxicology software and related endpoint models available to FDA/CDER for this purpose. It is mutually understood that the goal of the program is to support the discovery and development of new pharmaceutical entities to treat drug addiction for which the U.S. Congress has set a high national priority.